I’ve not done anything particularly scientific to measure but my observation is if symbols are fairly rare it doesn’t require a huge amount. Herobrine for instance as a string isn’t very common, so it seems to be pretty good at keeping in the semantic region. Steve and Alex are popular Minecraft characters but are not very unique so you see more drift. But the more you mix in specific semantics, like creepers, or other tokens that are pretty specific to the genre, things improve. You see similar behavior with stable diffusion Lora.

I’ve never seen it wander between genres, but it can tell pretty generic stories particularly if you’re pretty generic in your promoting.